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edit alexa prores4444 in fcp without destroying bit depth and color?
We are just getting starting on a multi facility vfx project and our first task to be completed is a vfx edit of the approved selects from the raw original camera footage. Files are prores4444 Log-C from Alexa. What I’d like to know is this; would it be possible to cut the selects in an FCP sequence and export to a flame readable uncompressed format without destroying the bit depth and color space of the Alexa files? To the best of my knowledge, FCP only supports 8-bit material when working with RGB and will often produce gamma shifts in this situation as well (thus destroying the Log-C curve). Will this hold true in my situation?
Thanks for any input.
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30 Replies
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FCP can edit ProRes 4444 natively just fine. Sequence settings for it and everything. How to get it to a Flame? No idea. But FCP edits PR4444 as 10 bit. Apple invented the codec, and the NLE supports it. It’d be silly if it didn’t.
Shane
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It certainly would be silly. So even though we’re talking 10bit RGB here, you’re saying that PR4444 is a situation where the 8-bit limitation of FCP’s RGB implementation and gamma shift issues no longer apply?
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[Adam Berk] “It certainly would be silly. So even though we’re talking 10bit RGB here, you’re saying that PR4444 is a situation where the 8-bit limitation of FCP’s RGB implementation and gamma shift issues no longer apply?”
ProRes 4444 can encode either RGB or YUV data (YUV lets you store subsampled color, it doesn’t require you to). It’s possible ProRes always represents itself to FCP as YUV to take advantage of high bit depth rendering, performing conversions internally. Red’s Redcode codec uses this trick, I think. I’ve never been able to find a definitive answer to this question.
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It’s great flying blind on this stuff isn’t it?
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Hi Adam,
You need third part software to render that in FC without destroying the bit depth.
FC can render just 8bRGB, so with that stuff you can only cut and export with NO RENDERING.
You can also make FC-Color and out keeping your bit depth.[Shane Ross] “FCP can edit ProRes 4444 natively just fine. Sequence settings for it and everything.”
FC can’t render 10b RGB.
When conform a sequence to Prores444, the sequence sets automatically to “Render in High Precision YUV”.
If you render and export that from FC, I don’t know what a heck you are getting?
Prores444 RGB?
Prores444 YUV?[Chris Kenny] “ProRes 4444 can encode either RGB or YUV data (YUV lets you store subsampled color, it doesn’t require you to). It’s possible ProRes always represents itself to FCP as YUV”
Prores444 needs further development yet. The color space (RGB or YUV) must be a choice on export.
Also needs an option for Video-Range/Full-Range, like any pro 10bRGB codec.
Hopefully on FCX.
rafael -
Has it been confirmed/tested/proven by anyone that it’s possible to do a cuts only edit of 10bit RGB material and export from FCP without modifying the picture data? Has apple confirmed this in a tech paper somewhere?
If so, does this rule also apply when exporting to a different codec than the source/sequence? In this example, I’d like to cut the PR4444 and export to a discreet readable 10bit RGB format. The prores import features on the discreet systems are highly unreliable and basically don’t work. If they did, we could avoid all of this.
Thanks so much for all the weekend responses.
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Just curious, why export? Why not give orig files/EDL/XML?
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[Adam Berk] “Has it been confirmed/tested/proven by anyone that it’s possible to do a cuts only edit of 10bit RGB material and export from FCP without modifying the picture data? Has apple confirmed this in a tech paper somewhere?”
Hi Adam,
I asked the people of “Sheer” (Bitjazz), to do that test.
They tested with their 10b/444/RGB (no Apple 10bRGB).
They compared the files (before/after FC with NO RECOMPRESSION) and they found that both files were identical pixel by pixel.
If there is not recompression, what you put in the time-line is what you get on export.
FC makes the movie putting together the cuts but keeps all the original setting.[Adam Berk] “If so, does this rule also apply when exporting to a different codec than the source/sequence? In this example, I’d like to cut the PR4444 and export to a discreet readable 10bit RGB format.”
The only problem is that any conversion in FC pass by going to 10bYUV. You would make 10 bRGB > 10bYUV > 10b RGB. FC would manage the color space conversion. If you don’t see any kind of gamma or color shifts, should be OK.
rafael -
Sorry if I wasn’t clear in my last post. The reason for conversion is that prores files can’t be reliably imported into the autodesk systems. This is a flame job.
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Ok. So theoretically, as long as we export using the same settings as what’s in the sequence, we should be fine. We could then theoretically take an EDL from the edited sequence, preconform in resolve with no grading and render out to DPX in source mode to get the individual shots in a format that’s compatible with our pipeline.
This sounds like a plan that may be worth a try.
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